AQA Qualifications GCSE MATHEMATICS (LINEAR) 4365/1H Mark scheme 4365 June 2014 Version 1.0 Final Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant questions, by a panel of subject teachers. This mark scheme includes any amendments made at the standardisation events which all associates participate in and is the scheme which was used by them in this examination. The standardisation process ensures that the mark scheme covers the students’ responses to questions and that every associate understands and applies it in the same correct way. As preparation for standardisation each associate analyses a number of students’ scripts: alternative answers not already covered by the mark scheme are discussed and legislated for. If, after the standardisation process, associates encounter unusual answers which have not been raised they are required to refer these to the Lead Assessment Writer. It must be stressed that a mark scheme is a working document, in many cases further developed and expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark schemes on the basis of one year’s document should be avoided; whilst the guiding principles of assessment remain constant, details will change, depending on the content of a particular examination paper. Further copies of this Mark Scheme are available from aqa.org.uk Copyright © 2014 AQA and its licensors. All rights reserved. AQA retains the copyright on all its publications. However, registered schools/colleges for AQA are permitted to copy material from this booklet for their own internal use, with the following important exception: AQA cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third party even for internal use within the centre. MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Glossary for Mark Schemes GCSE examinations are marked in such a way as to award positive achievement wherever possible. Thus, for GCSE Mathematics papers, marks are awarded under various categories. M Method marks are awarded for a correct method which could lead to a correct answer. A Accuracy marks are awarded when following on from a correct method. It is not necessary to always see the method. This can be implied. B Marks awarded independent of method. Q Marks awarded for quality of written communication. M dep A method mark dependent on a previous method mark being awarded. B dep A mark that can only be awarded if a previous independent mark has been awarded. ft Follow through marks. Marks awarded for correct working following a mistake in an earlier step. SC Special case. Marks awarded for a common misinterpretation which has some mathematical worth. oe Or equivalent. Accept answers that are equivalent. e.g. accept 0.5 as well as 1 2 [a, b] Accept values between a and b inclusive. [a, b) Accept values a ≤ value < b 25.3 … Allow answers which begin 25.3 e.g. 25.3, 25.31, 25.378. Use of brackets It is not necessary to see the bracketed work to award the marks. 3 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Examiners should consistently apply the following principles Diagrams Diagrams that have working on them should be treated like normal responses. If a diagram has been written on but the correct response is within the answer space, the work within the answer space should be marked. Working on diagrams that contradicts work within the answer space is not to be considered as choice but as working, and is not, therefore, penalised. Responses which appear to come from incorrect methods Whenever there is doubt as to whether a candidate has used an incorrect method to obtain an answer, as a general principle, the benefit of doubt must be given to the candidate. In cases where there is no doubt that the answer has come from incorrect working then the candidate should be penalised. Questions which ask candidates to show working Instructions on marking will be given but usually marks are not awarded to candidates who show no working. Questions which do not ask candidates to show working As a general principle, a correct response is awarded full marks. Misread or miscopy Candidates often copy values from a question incorrectly. If the examiner thinks that the candidate has made a genuine misread, then only the accuracy marks (A or B marks), up to a maximum of 2 marks are penalised. The method marks can still be awarded. Further work Once the correct answer has been seen, further working may be ignored unless it goes on to contradict the correct answer. Choice When a choice of answers and/or methods is given, mark each attempt. If both methods are valid then M marks can be awarded but any incorrect answer or method would result in marks being lost. Work not replaced Erased or crossed out work that is still legible should be marked. Work replaced Erased or crossed out work that has been replaced is not awarded marks. Premature approximation Rounding off too early can lead to inaccuracy in the final answer. This should be penalised by 1 mark unless instructed otherwise. 4 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Paper 1 Higher Tier Answer Q Mark 1(a) Expression B1 1(b) Formula or equation B1 1(c) Identity B1 Comments 5 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Alternative Method 1 (CD = £) 45 – 35 or 10 or 2d + c = 35 and 2d + 2c = 45 M1 (35 – their 10) ÷ 2 or (45 – 2 × their 10) ÷ 2 or 22.5 – their 10 or 12.5(0) M1 Condone missing brackets or a pair of values that satisfy one of the statements 3 their 10 + their 12.5(0) M1dep 42.5(0) or 7.5(0) remaining A1 Dep on second M Strand (iii) Correct conclusion based on their total ft correct conclusion based on their total if two Ms awarded. Q1ft 2 NB the difference between the cost of 3 CDs and 50 may be calculated and compared to the cost of a DVD to reach a conclusion. eg 50 – 3 10 = 20 > 12.5 so Yes is full marks. Alternative Method 2 (Trial and Improvement) Chooses a value for CD and DVD and tests in both statements M1 Chooses a new value for CD or DVD or both and tests in both statements M1dep Finds a pair of values for CD and DVD that the student thinks works in both statements and calculates 3 their CD + their DVD M1dep 42.5 (0) Correct conclusion based on their total A1 Strand (iii) Q1ft ft correct conclusion based on their total if three Ms awarded. 6 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 3(a) Four different numbers in any order with median 5 and range 7 B2 B1 Four numbers in any order with median 5 and range 7 with repeats eg 4, 4, 6, 11 eg 1, 4, 6, 8 3, 3, 7, 10 9, 6, 4, 2 1, 5, 5, 8 3, 10, 6, 4 5, 5, 4, 11 1, 3, 7, 8 B1 2, 3, 7, 9 Four different numbers in any order with median 5 or range 7 0, 4, 6, 7 1.5, 4, 6, 8.5 –1, 4.5, 5.5, 6 7 6 or 42 or 3(b) 8 9 or 72 or 9 4 or 36 or M1 10 1 At least one product shown or one correct value (not 10) or 160 Must have the sum of 4 products divided by 20. (their 42 + their 72 + their 36 + their 10) ÷ 20 M1 dep Condone missing brackets (7 6 + 8 9 + 9 4 + 10 ( 1)) ÷ 20 is M2 8 A1 7 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Answer Q 4(a) 4(b) Mark 5×8 M1 40 A1 cm2 B1 Any quadrilateral that has neither line nor rotational symmetry. Ie Comments oe ½ (8 + 8) 5 Rotations, translations and reflections of these. B1 Must use dots as vertices. Condone internal lines if a clear quadrilateral is outlined. Lines do not need to be ruled. 5(a) B1 for answer of 2 or 3 or 2 3 B1 for 24 = {2, 2, 2, 3} or 2223 or 42 = {2, 3, 7} or 2 3 7 or 6 B2 one pair of factors of 24 (not 1 24) eg 2 × 12, 3 and 8, 24 ÷ 4 = 6 (oe) and one pair of factors of 42 (not 1 42). eg 2 × 21, 3/14, (6, 7) (oe) or (24 =) {1, 2, 3, 4, 6, 8, 12, 24} or (42 =) {1, 2, 3, 6, 7, 14, 21, 42} 8 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 5(b) 48 as a correct product (except 1 48) eg M1 Ignore incorrect products if at least one correct product seen. 2 24 or 3 16 or 6 8 or 2 3 8 or (2, 24) or (1, 2, 3, 8) etc 6 2 2 2 2 3 or 24 × 3(1) or 23 2 3(1) or 22 22 3(1) A1 D, B, C B2 π 5 or π 10 ÷ 2 or 2 π 5 ÷ 2 B1 for 2 correct Accept numerical values eg 31 ÷ 2 M1 Allow π = 3 15.5 A1 Accept 15.7 or 15.71 25.5 A1ft or 5π 7 oe eg 48 ÷ 2 = 24 or branches on a prime factor tree showing at least one product or factor ladder showing a correct division. Answer Q ft 10 + their 15.5 Accept 25.7 or 25.71 SC2 5π + 10 Mark 6 B1 –6 B1 8(a) Comments Allow embedded answers ie 6 6 = 36, 62 = 36, -62 = 36, –6 –6 = 36 B2 for ±6 9 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Alternative method 1 Ignore any denominators. This is the numerator of the left hand side. 8(b) If expanded straight away allow one sign or numerical error 2(y + 1) + 3(y – 2) or 2y + 2 + 3y – 6 M1 Invisible brackets must be recovered for M1 eg 2 y + 1 + 3 y – 2 = 5y – 1 is M0 2(y + 1) + 3(y – 2) = 12 or 2y + 2 + 3y – 6 = 12 is M2 5y – 4 A1 Their 5y – 4 = 12 M1 3.2 A1ft Could be implied by rearrangement eg 5y = 6 from 2y + 2 + 3y – 6 = 2 oe eg 5y + 2 = 18 oe eg ft on both Ms awarded and at most 1 error. Alternative method 2 M1 Allow one sign or numerical error A1 M1 3.2 A1ft This is for rearranging their LHS = 2 with variable on one side and numbers on the other with terms simplified. oe eg ft on both Ms awarded and at most 1 error. 10 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 9(a) a=6 B1 Allow 6x SC1 if values reversed. b = 100 B1 y = 6x + 100 seen in script with no contradictory answers for a and b given allow B2 Alternative Method 1 9(b) y = their 6 80 + their 100. Substitution of 80 into their formula M1 580 A1ft ft their formula 400 + (280 – 100) M1 Or use of values from graph 580 A1 One comparison on means but must clarify what this implies B1 Their 6 must have a value, ie not 0. Alternative Method 2 10 One comparison on interquartile ranges but must clarify what this implies B1 eg mens mean is lower so they are faster (on average) Women are slower on average Women are more consistent as their IQR is smaller Men’s times more varied as IQR bigger 11 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 11 Alternative Method 1 (P:) (D =) 90T or (M:) (D =) 70(T + 1) M1 oe 90T = 70(T + 1) M1dep Condone missing bracket, ie 90T = 70T + 1 but no further marks unless bracket recovered, 90T – 70T = 70 M1dep oe NB 70 ÷ 20 is M3 3.5 A1 oe 3.30 is M3, A0 Alternative Method 2 Chooses a value for distance travelled and correctly works out time taken at 90kph and time taken at 70kph Lists distance travelled for Paul and Mary (for at least 2 hours) M1 Eg 90, 180, 270, 360, … 70, 140, 210, 280, 350, …. Subtracts their values or repeats above with a different value M1dep Trying a new value implies that the difference between previously calculated times was not 1. Chooses a different value for distance travels and correctly works out time taken at 90kph and time taken at 70kph, but the difference in times must be closer to 1 hour than the previous choice. M1dep oe 3.5 A1 oe 3.30 is M3, A0 SC2 315 km Alternative Method 3 (P:) (D =) 90(t – 1) or (M:) (D =) 70t M1 NB this scheme is for working out the time that Mary takes. It can be ‘recovered’ for full marks but if it ends at 4.5 then 2 marks maximum. oe 20t = 90, and t = 4.5 M1dep NB 90 ÷ 20 = 4.5 is M2 Their 4.5 – 1 M1dep oe 3.5 A1 oe 3.30 is M3, A0 12 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Answer Q B Mark A, B Comments Mark the diagram first and only look in working space if blanks in diagram. 0.12 0.4 A 0.3 0.6 Not B A, Not B B 12 0.7 0.18 Not A, B 0.28 0.4 B 0.6 Not B Not A, Not B 0.42 P(B) = 0.4 B1 P(Not A) = 0.7 and 1 – their 0.4, and same probabilities on both second branches B1ft Any 1st event and 2nd event probability multiplied together M1 Follow through their values even if 0.7 wrong, but probabilities must be 0 < p < 1 Full correct final probabilities A1ft ft their probabilities 13 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Alternative Method 1 x + y = 15 and x – y = 8 M1 oe Attempt to solve by eliminating x or y M1 Eg 2x = 23 or 2y = 7 x = 11.5 or y = 3.5 A1 A1 ft ft on one error but only for one variable. eg if x calculated wrongly but then substituted and y calculated correctly allow A0 for x but A1 ft for y y = 3.5 and x = 11.5 13 SC2 correct answers but no working or by T&I Alternative Method 2 13 a and 15 – a M1 15 – a – a = 8 M1 a = 3.5 A1 b = 11.5 A1 ft SC2 correct answers but no working or by T&I Alternative Method 3 b and b + 8 M1 b and b – 8 oe b + b + 8 = 15 M1 oe b + b – 8 = 15 b = 3.5 A1 b = 11.5 a = 11.5 A1 ft a = 3.5 SC2 correct answers but no working or by T&I 14 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Answer Q 3x(4x + 1) – 2(6x – 3) Mark M1 14(a) Comments if expanded straight away allow one sign or arithmetic error eg 12x2 + 3x – 12x – 6 (Must have an x2 term, 2 ‘x‘ terms and a constant term) Condone missing brackets eg 3x 4x + 1 – 2 6x – 3 12x2 + 3x – 12x + 6 A1 12x2 – 9x + 6 = 6 2 or 12x – 9x = 0 oe M1 or 12x2 = 9x If their equation in (a) is 12x2 – 9x – 6 leading to 12x2 – 9x – 12 = 0 award M1 use of formula or completing the square oe 14(b) x(12x – 9) or 3x(4x – 3) or x(4x – 3) or 12x = 9 M1dep or (x – )2 = oe from equation above oe 3 x= 4 A1 If x = 0 given do not award A1 15 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 15 AD = AE (10 (cm) or sides of a square) or sides marked as 10 on diagram B1 Must give a reason or mark sides as 10 on diagram AB = AG (10 (cm) or sides of a square) or sides marked as 10 on diagram B1 Must give a reason or sides as 10 on diagram Angle DAG = angle EAB (135 or 90 + 45) B1 Must state 135 or 90 + 45 or 135 shown for both angles on diagram Q1 Q0 for congruent without SAS, AAS etc or the appropriate reason for their proof stated in words (strand (ii)) Congruent due to SAS (could be expressed in words eg two sides and angle between them the same) or congruent due to ASA or AAS or SAA with 22.5 shown or stated (after 135 seen) as one of the other angles. (could be in words eg two angles and the side between them, or two angles and a side) Sight of x2, –xy, +xy and –y2 plus some indication that xy terms cancel. 16(a) Eg x2 – xy + xy – y2 B1 Minimum would be x2 – xy + xy – y2 = x2 – y2 16 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Alternative method 1 16(b) 3 +1 1 5√2 (√3 – 1) 2 2 2 B1 Correct substitution into ½ absinC ( 3 – 1)( 3 + 1) = 3 – 1 (= 2) B1 This must be evaluated at some stage Q1 Must show or state cancelling (strand(ii)) for justifying a result. Clear indication that the expression cancels down to a fraction equivalent 5 to 2 Cancelling can be done at any stage Alternative method 2 Height = (√3 – 1) 3 +1 2 2 = B1 that ( 3 – 1)( 3 + 1) = 3 – 1 (= 2) 16(b) 1 5√2 their 2 Clear indication that the expression cancels down to a fraction equivalent 5 to 2 Must get this correct to show explicitly or implicitly (eg could rationalise denominator) B1ft Q1 Must show or state cancelling (strand(ii)) for justifying a result. Cancelling can be done at any stage 17 of 18 MARK SCHEME – GCSE Mathematics (Linear) – 4365/1H – June 2014 Answer Q Mark Comments Alternative Method 1 Volume original = 1 10 10 30 3 10 10 could be 102 M1 Accept 0.33 or better for (= 1000) Volume removed = 1 5 5 15 3 5 5 could be 52 M1 1 (10 10 30 – 5 5 15) is M2 3 A1 Correct answer only (= 125) 875 17 Alternative Method 2 Volume original = 1 10 10 30 3 10 10 could be 102 M1 Accept 0.33 or better for (= 1000) (Linear scale factor 1 so) volume 2 1 7 scale factor or 8 8 18(a) 1 3 1 3 M1 875 A1 Correct answer only Substitution of x = 0 into equation M1 – 1 A1 1 1 – 15 15 1 (2 their midpoint + 1)(2 their 15 midpoint – 15) B1 for – 18(b) – 1 (2 3.5 + 1)(2 3.5 – 15) 15 B2 or substituting into their expanded expression. B1 for graph intersects at x = –0.5 or midpoint = 3.5 18 of 18